Infants and other incontinent individuals wear disposable absorbent articles such as diapers to absorb and retain urine and other body exudates. Absorbent articles may function both to contain the discharged materials and to isolate these materials from the body of the wearer and from the wearer's garments and bed clothing. Diaper users of all ages present a variety of body shapes and sizes. Thus, diapers are generally provided in a range of sizes to accommodate different body types and sizes. A particular diaper wearer, such as an infant or young child, may also grow rapidly. Diapers are sometimes sold in “bulk packs” containing large quantities of diapers, which may contain 200 diapers or more in a single sales unit. However, an infant may need a larger diaper size before an entire bulk pack is used. Thus, purchasing diapers presents a conundrum for caregivers, who must wager on whether they should spend more (per diaper) for a smaller pack of diapers, so that an infant is unlikely to outgrow the diaper size before the diapers are used, or whether they should spend less (per diaper) for a bulk pack of diapers, some portion of which may be discarded if the diapers are outgrown by the infant before all the diapers are used. This problem may also arise with incontinent adults, such as recovering invalids who are regaining weight lost during illness or injury.
Diapers can be configured to fit on a wearer's body in various ways. For example, some diapers may be configured as pull-on, pant-type diapers or training pants. Diapers, including training pants, may be used with infants prior to and/or during toilet training. Training pants may be configured with a “closed” chassis configuration, in which the chassis is adapted to be pulled on over the legs and lower torso of the wearer without any additional fastening steps. Other diapers may be configured as a “taped diaper,” in an “open” chassis configuration, in which the chassis is adapted to be applied to the wearer by wrapping the diaper around the user and fastening the diaper to itself, usually at or near the waist of the wearer.
Closed chassis diapers may be manufactured with a front ear being seamed to a back ear to form the closed chassis. In some configurations, closed chassis diapers may also have manually tearable side seams. The side seams may be configured as butt-type seams or overlapping side seams.
During the manufacturing process, a closed chassis diaper may be manufactured from a blank cut to a particular configuration and size. Manufacturing processes may involve some type of sealing step to create side seams in the diapers. For example, after being fully assembled, the blank may be folded along a central transverse area and the sides of the front and rear panels are seamed together to form a closed chassis diaper. In other processes, the side seams may be formed by folding the chassis in a crotch portion so that longitudinal side regions of the front portion and rear portion are superposed to form seaming areas, which are then treated with ultrasonic energy to sever the material in the seaming area in a first area while simultaneously bonding the material of the seaming area in a marginal area adjacent the first area to form a flangeless seam.
In some manufacturing configurations, the seaming and folding operations may be performed automatically on a processing wheel having a plurality of folding stations and associated seaming mechanisms. Various types of such processing wheels have been described in U.S. Patent Publication No. 2008/0083489 and U.S. Pat. Nos. 5,779,831 and 7,322,925, each of which is hereby incorporated by reference herein.
The processing wheels provide the ability to produce training pants at a high rate of speed. However, reconfiguring various components of the processing wheel to change manufacturing operations for different sizes of absorbent articles can be onerous. For example, some components of the processing wheel may require realignment, which can be time consuming and expensive. For instance, different size folding stations may be needed to accommodate a different sized diaper. Such different sized folding stations may need to be realigned with the seaming stations. In addition, different sized folding stations may also require changes in the physical locations of operating stations, such as the discharge station, located adjacent the processing wheel.
Prior methods of manufacturing diapers suffered from problems of difficulty of control of the web material and the diaper subcomponents. Because of the control difficulty, prior methods were limited in overall production speed and produced a lower quality end product. Furthermore, every different size of diaper required a different machine that was sized to seam the individual size of diaper. As a result, diaper production required separate production lines for each size of diaper, which resulted in large capital outlays and more expensive maintenance.